The wonderful world of primate poo (and why it really matters)

By Catryn Williams, on 17 August 2017

As a biology PhD student, I’ll be the first to admit that there are some studies in science that, whilst interesting, can leave you questioning who comes up with these and why they (and we) should care so much.  If you, like me, are the kind of person who loves these kinds of things, the list of past Ig Nobel prize winners is a cornucopia of great examples.  Often, though, all it takes is delving a little deeper to find the importance in what seems like a pointless topic.  My PhD involves collecting primate poo samples to look at their gut bacteria, and so does occasionally elicit the classic and very valid question: “But what’s the point of it?” from people, so I thought for this week’s blog post I’d try and answer exactly that.

Primates are our closest relatives and, in fact, your closest relatives are also primates, as are you yourself.  We’ve known about the anatomical similarities between humans and other, non-human primates for hundreds of years.  The Grant Museum of Zoology plays host to what used to be a teaching collection for doctors studying at UCL, where the bones and structures of animals from non-human primates to fish would be studied to understand how our own bodies developed from the ancestors we shared with other organisms.  Then, in the 1980s, with the birth of molecular sequencing techniques, we gained the ability to study the DNA of animals.  From this we began to understand just how closely related to other primates we really are, leading us to the famous fact that we are 98% genetically identical to chimpanzees, our closest relative.


A juvenile chimpanzee skeleton from the Grant Museum of Zoology, accession number Z449

The next big step, in my (admittedly, probably biased) opinion, in our understanding of the human body and how it works has been our realisation that gut bacteria are hugely important to human health and disease.  We might tend to think of bacteria as harmful or infectious, but actually the bugs that live in your intestine are a normal part of a healthy human body.  They outnumber our own cells 10 to 1, making us 90% bacteria in terms of cell numbers alone (although our own cells are much larger, which is why by mass we’re still mostly human), break down parts of our food that we ourselves can’t digest and even provide us with many hormones (such as 90% of our serotonin, the “happiness” hormone).  In addition, gut bacteria has lately been linked to everything from keeping us lean or helping to make us obese, to maintaining normal bowel functions or exacerbating conditions such as irritable bowel syndrome.

So where do non-human primates come into this?  Well, as with the Grant Museum’s collection all those years ago, it’s nothing new to study our relatives in order to understand more about ourselves.  While understanding the gut bacteria of primates across the whole primate evolutionary tree lets us take a look at how gut bacteria have evolved alongside us to create a mutualistic relationship, primates in particular are a very interesting group of animals.  Within the Primate Order there is huge variation in the ways that these animals live their lives, and it is by considering these differences that we can begin to understand how the variations between different human lifestyles affect our gut bacteria and so our health.  For example, by comparing primates that eat mostly vegetation to species that eat fruit or meat or even gum like lorises, we can start to ask questions about how much our diet affects what bacteria can survive in the gut.  Looking at animals that are highly social, such as chimpanzees or baboons, vs. those that are mostly solitary creatures such as bushbabies can tell us how gut bacteria is spread and shared between individuals, communities and even between different species living in the same area (this is not as crazy as you think – humans have been found to share skin bacteria with their pet dogs).

Primate species, diet and social structure are all thought to be important in determining an animal's gut bacteria

Primate species, diet and social structure are all thought to be important in determining an animal’s gut bacteria. Licensed under Creative Commons CC0 1.0

But it’s not just ourselves that we can learn things about when we study non-human primates.  One large aspect of my PhD looks at how life in captivity affects the gut microbiomes of primates.  Whilst life in captivity is not ideal for any animal, raising them in zoos and centres can have benefits for endangered species.  Studying the gut bacteria has the potential to offer suggestions on how we might be able to enrich the diets of captive animals to ensure they maintain healthy gut bacteria whilst living in zoos.  Furthermore, by looking at what nutrients are necessary to keep a healthy set of bacteria, we might be able to start thinking about conservations issues such as which plants are highly important to conserve alongside these endangered animals.

So, I hope I’ve convinced you that gut bacteria are important, that my area of research has the potential to be of great help, and above all, that primate poo is a great thing to study.

A Physicist’s Guide to Zoology

By Catryn Williams, on 21 February 2017

As any lover of Attenborough will, I’m sure, understand, the idea that someone is not naturally interested in nature and zoology is something that I, as a researcher of primates (specifically, their gut bacteria), had never really considered before. Aware as I am that the fascinating but visually underwhelming (I’m sorry!) sea squirt might take a bit of effort to enthuse people I sort of assumed a general underlying love of at least all the four-legged, big-eyed, furry, woolly things of the world.

This wholly unreasonable assumption of mine was proven wrong during last week’s shift at the Grant Museum by one simple question from a very enthusiastic and lovely retired physicist:

“What would a group of physicists find interesting in a Zoology museum?”

What follow here are just two examples of nature seen through a different lens, which I hope go some way towards enthusing those not naturally curious about zoology.

All that glitters isn’t gold, all that shimmers isn’t green

Most of the green birds you see are pretenders.  Rather than truly being green, they’re a beautiful example of something called structural colouring.

When you use paint to colour a surface, what you are applying are coloured molecules, called pigments.  These produce colour through absorption of different wavelengths of light; to produce green, for example, red and blue light are absorbed whilst green light is reflected into your eyes.


The Green Honeycreeper, not a green bird. Photo credit: CC Image courtesy of Lip Kee on Flickr

First observed by Robert Hooke and Sir Isaac Newton and explained by Thomas Young a century later, structural colouring, however, is the production of colour through the interference of white light by microscopic surfaces, rather than absorption of certain wavelengths.  This can work in conjunction with pigments — for example, a peacock feather is pigmented brown, but microscopically structured so that they reflect blue and green light, and also making them iridescent, showing different colours depending on the angle from which you view them.

Structural colouring in animals, particularly birds, can be a big evolutionary advantage.  Creating pigments can be very energy-costly, and often requires rare elements that are difficult to extract from food during digestion, such as metals like cadmium, cobalt or chromium for green pigments.  Structural colouring is an ingenious way to create these brilliant colours through feather shape alone, hugely useful when trying to attract a mate or hide from predators in the trees.

Turacos are the interesting exception to these structural colourists.  Found in forests and woodlands in sub-Saharan Africa, these birds actually produce their own unique red and green pigments, called turacin and turacoverdin respectively, using an unusually high amount of copper.  Just why they make this pigment is still a mystery.  Their habitat coincides with the world’s richest copperbelt, leading some to speculate that this pigment production might’ve evolved to detoxify the large amount of copper these birds ingest through their food.  Whatever the reason, this unique ability to use copper in this way makes turacos some of the only truly green birds.

A truly green Angolan Turaco. Photo credit: C. P. Ewing

A truly green Angolan Turaco. Photo credit: CC Image courtesy of C. P. Ewing on Flickr

There are many examples of structural colouring in the Grant Museum, from the peacock’s feather to the wings of iridescent butterflies and the gold sheen of some beetles.  I highly recommend seeing how many you can spot next time you’re there.


A (constructal) theory of everything


It might not be the unified theory that Stephen Hawking is searching for, but the Constructal Law is a physics theory that can be used to explain the shapes of all the bones, limbs and preserved animal specimens that you see around you in the Grant Museum.

In its simplest form, Constructal Law states that systems naturally evolve over time to minimise energy waste.  Substitute the word “animals” for “systems”, and you have its application to zoology.  This seems like an obvious benefit; wasting less energy allows animals to get the most out of the food they eat, allowing them to flee from predators faster, spend less time gathering food and more time chatting each other up, and produce better-fed offspring. Where this rule becomes most interesting though is when you consider animal locomotion.

Even though running, flying and swimming have all evolved as separate methods of locomotion, they’re all linked by this simple physics principle.  Despite involving very different body mechanics, it turns out that there is a universal relationship between animals’ mass and speed, as well as the frequency and force of limb or tail movement, whether those are legs, wings or fins.  The relationship between a winged animal’s mass and the frequency of their wing beats shows the same relationship as between mass and rate of swimming in fish, as well as mass and stride frequency in running animals, and has all evolved to move the animal at optimal speed, reducing energy wastage whilst maintaining quick movement.  No other factors, such as type of creature, limb length, wingspan or otherwise, seem to factor in to this, only body mass and limb or tail movement.

Grant Museum

Paddling and running on display at the Grant Museum. Photo credit: CC Image courtesy of Justin Pickard on Flickr

This principle helps determine how animals move around and is a brilliant example of how the great diversity of life still converges to fit fundamental physics principles.  Next time you’re in the Grant Museum, have a think about how all the animals around you have been shaped in part by this universal law.

The physicist I met got me to consider the animal specimens in the museum from a whole new angle, making me think about what different people would find interesting about zoology and, importantly, why, rather than just assuming everyone has an inbuilt love.  Just like the iridescent wings of certain animals, looking at a familiar collection from a different angle can offer a whole new view on zoology.  And seriously, give the sea squirt a chance.

A Novel Idea: Popular Culture Influences in Zoology

By Arendse I Lund, on 18 August 2016

ArendseBy Arendse Lund

Hidden in one of the far cabinets in the Grant Museum, nestled amongst parasites and other unusual filter feeders, sits a much overlooked worm. This invertebrate marine creature is known as a Chaetopterus and is unusual because it has lived its whole adult life in a tube constructed from underwater sediment and attached to a rock. More colloquially though, the Chaetopterus is referred to as a parchment worm.

Parchment Worm

This worm (image on the right, Grant Museum, G52) has actually nothing in common with parchment, which usually is made of calf-, sheep-, or goatskin and used to create manuscripts. Nor does it have anything to do with those worms that destroy manuscripts to the detriment of scholarship everywhere. Actually, it takes its name from the papery, parchment-like burrows it lives in.

Similar to how visitors who are fans of Pokémon are thrilled to espy some of the animals the monsters are based on, book-loving visitors to the museum seem to take great delight in this worm’s name, granting it a celebrity status higher than it might otherwise have. A worm, by any other name, might not be as popular.

Literary lovers will also be happy that spiders and other arachnids have book lungs, respiratory organs unrelated to the lungs of humans. This diagram from John Henry Comstock’s aptly titled The Spider Book depicts a cross section of a spider’s book lung. These lungs are arranged with horizontal, leaf-like folds. Composed of stacks of alternating air pockets, these “pages” usually do not need to move to work. Similarly, horseshoe crabs have book gills, which are external appendages rather than internal organs.

Spider Book Lung

Figure 2: A spider’s book lung with the #3 marking the leaves of the book lung (Comstock, The Spider Book, pg. 146)

Luckily for fans of whimsy, there is a fair amount of freedom involved in describing or naming species. The International Code of Zoological Nomenclature instructs that: “Authors should exercise reasonable care and consideration in forming new names to ensure that they are chosen with their subsequent users in mind and that, as far as possible, they are appropriate, compact, euphonious, memorable, and do not cause offence.” This leniency with naming animals, in comparison to naming astronomical bodies, has allowed for newly discovered species to be named after expedition benefactors, popular celebrities, and even mythical creatures.

In the late 1990s, a species of turtle was dubbed Psephophorus terrypratchetti after Terry Pratchett, whose Discworld series takes place on that back of a giant turtle. A species of ancient lizard was given the moniker Clevosaurus sectumsemper as an allusion to the vicious spell Severus Snape invents in the Harry Potter series. Similarly, a 66 million year-old dinosaur was named Dracorex Hogwartsia, or the “Dragon King of Hogwarts,” and resembles the fictional Hungarian Horntail. Dragons seem to be a popular source of naming inspiration: Two recently discovered ants were even named after Daenerys Targaryen’s dragons from Game of Thrones: Pheidole drogon and Pheidole viserion.

Pheidole Viserion

Figure 3: Pheidole viserion, whose spiked appearance and blonde color caused it to be named after the dragon from Game of Thrones. (Photo: Okinawa Institute of Science and Technology).

While all these are fairly straight-forward allusions to fictional works, one paleontologist took it even further when she discovered a fossil tetrapod near a quarry in Scotland. She developed a name which only works in translation: Eucritta melanolimnetes, or “the true creature from the black lagoon.”

Sometimes that creativity fails though. An early twentieth-century biologist, overwhelmed at the prospect of naming a whole slew of new moth species at once, decided on: Eucosma bobana, E. cocana, E. dodana, E. fofana, E. hohana, E. kokana, E. lolana and E. momana.

But with thousands of new species discovered a year, perhaps that’s understandable.

The Alligator: Man-Eater or Misunderstood?

By Gemma Angel, on 1 July 2013

Sarah Savageby Sarah Savage






While browsing the cases during an afternoon’s engagement session in the Grant Museum, I spotted a very familiar face from my life in New Orleans: the American alligator. As one of the largest, most terrifying reptiles I have ever encountered in real lofe during my walks in the Louisiana swamps, the alligator earns my respect as the king of the wetlands. Staring into the display case, a young student visitor from London approached and remarked, “Is that a dinosaur?!”

Alligator at the Grant

Alligator skull in the Grant Museum of Zoology.

Despite the alligator’s large, scaled form reminiscent of a prehistoric water monster, the alligator is of course not a dinosaur. The student appeared quite distressed that alligators still exist and live in the swamps in the southern United States. I described what it is like to observe a wild alligator in person, only seeing the large eyes above the water at first, until the beast decides to fully surface.

lurking alligator

Alligator in the wild.

Although the alligator is a predator, it does not pose a direct threat to human visitors in the swamps as long as a distance is maintained between the visitor and alligator. When I was quite young, I remember learning how to outrun an alligator if by chance our paths crossed. Since alligators are remarkably fast ambulators on land, it is best to run in a zig-zagging line if you find yourself being chased by one of these prehistoric-looking creatures. Due to the nature of the alligator’s short legs and long, heavy body, it is difficult for alligators to make sudden turns. The young visitor to the Grant was also intrigued by the long, sharp teeth visible in the alligator’s jaw in the display. Alligators can have between 2,000 and 3,000 teeth over a lifetime, as new teeth replace those that become damaged. The muscles within an alligator’s jaw are very powerful, allowing the jaw to quickly snap shut on prey to prevent it from escaping. In fact, the pressure of an adult alligator’s jaw is approximately 300 pounds per a square inch. Luckily for humans, an alligator’s primary diet consists of fish, birds, amphibians, small reptiles such as snakes and turtles, and small mammals living in the wetlands. Examples of these small mammals include rats, nutria, mice, opossum, squirrels, raccoons, muskrat, and infant deer. Although some of an alligators’ prey can be quite small, occasionally alligators can feed upon fully-grown deer or feral boars. There are occasional alligator attacks on humans – however, most of these are a case of mistaken identity. Unlike the alligator’s cousin, the crocodile, which will actively hunt humans, alligators are wary of contact with humans.



Upon further examination of the alligator and crocodile skulls in the display case, I noted two very distinct features that are classic indicators which distinguish between the beasts. The first feature is the relative shape of their skulls. The alligator has a broader snout than the thin, long snout of the crocodile. Secondly, the alligator has larger, wider teeth as compared with the long, thin teeth of the crocodile. In the Audubon Zoo in New Orleans and on swamp tours in Southeast Louisiana, a visitor can even hold a baby alligator without the threat that the alligator will turn on the human. Although not the most conventional of baby animals to hold, baby alligators have smooth, scaly skin and soft underbellies. Beware of baby alligators in the wild though; their human-like cries, similar to those of a human child’s, mean that there is very likely a ten-foot or larger mother alligator nearby lurking just under the surface of the water.

Group of baby alligators.

Group of baby alligators.

However, from the safety of the Grant Museum, visitors can examine alligator and crocodile skeletons up close.